A male of any age that has the emotional and sexual mind set of a young boy with the added desire to be a wife to a dad or father figure.
Often this desire is enhanced by a desire to have all of the abilities of a female, (lactation, and childbirth) without the need for a sex change surgery.
A true boy-wife will maintain his body appearance as a young boy, often without body or pubic hair.
A boy-wife is not a transexual, transgender or cross dresser, but when in wife mode, often utilizes some form of minimal female clothing; (ie; panties, night gown.)